1. Field of the Invention
The present invention relates to an analytical instrument field, specifically an instrument for pharmaceutical micromolecular and biological macromolecular ion generation.
2. Description of the Related Art
It has been two decades since John B. Fenn, one of the laureates of Nobel Prize in Chemistry for 2002, applied Electrospray Ion (ESI) source to macromolecular mass spectrometry in the mid 1980s, but the ESI source mechanism still stays in two models: Ion Evaporation Model (IEM) and Charged Residue Model (CRM). The basic structure of ESI source has no essential difference with that in the 1990s.
The basic structure of ESI source is filling a hollow metal or glass capillary tube with liquid against the ion inlet of the mass spectrum, applying positive or negative high voltage to the liquid, wherein positive and negative ions are formed in the atmosphere, and the vacuum system of the mass-spectrograph absorbs some of ions into the mass analyzer of the mass-spectrograph.
For the ESI source, although the ionization probability is so high as to almost reach 100%, effective ions which transfer molecular ions to the MS (mass spectrum) mass detector range from 0.01% to 0.1% of the total number of ions.
To solve the aforementioned problem, many inventors discovered ESI sources of different mechanisms, in which their reference patent numbers are U.S. Pat. No. 4,861,988, U.S. Pat. No. 5,412,208, U.S. Pat. No. 5,432,343, U.S. Pat. No. 6,992,299 and U.S. Pat. No. 5,504,329. However, all of these prior inventions put the emission needle of the ESI source in the air. As the ion flow and the liquid flow are closely related, steady ion emission cannot be obtained within a large flow range of 100 nl/min-200 ul/min and there are no substantial improvements in the ion transmission efficiency by these prior arts.